Question

Срочно, даю 20 балов. катер по течению реки прошёл расстояние за 1,4часа, а против течения за 0.8часа, все расстояния которые он прошёл равно 34,2км . найдите скорость течения если скорость катера 15км/час. Решить задачу уравнением

Answer 1

Ответ:

2 км/ч

Пошаговое объяснение:

Пусть х км/ч - скорость течеия реки, тогда (15+х) км/ч - - скорость по течению, а (15-х) км/ч - скорость против течения.

1,4*(х+15) км - путь по течению, а 0,8*(15-х) км - путь против течения.

Составим уравнение 1,4*(15+х)+0,8*(15-х)=34,2

21+1,4х+12-0,8х=34,2

0,6х=34,2-33

0,6х=1,2

х=1,2:0,6

х= 2 км/ч - скорость течения реки

Answer 2

To solve this problem, we can set up an equation using the formula:

Distance = Speed × Time

Let's denote the speed of the current as 'c' (in km/h).

When the boat is moving with the current, its effective speed is the sum of its own speed and the speed of the current. So, the boat's speed with the current is (15 + c) km/h.

When the boat is moving against the current, its effective speed is the difference between its own speed and the speed of the current. So, the boat's speed against the current is (15 - c) km/h.

Given that the boat traveled a total distance of 34.2 km, we can set up the following equation:

(15 + c) × 1.4 + (15 - c) × 0.8 = 34.2

Let's solve this equation to find the speed of the current 'c'.

Solving the equation:

Expanding the equation, we get:

21 + 1.4c + 12 - 0.8c = 34.2

Combining like terms, we have:

33.4 + 0.6c = 34.2

Subtracting 33.4 from both sides, we get:

0.6c = 0.8

Dividing both sides by 0.6, we find:

c = 0.8 / 0.6

Simplifying, we get:

c = 1.333...

Therefore, the speed of the current is approximately 1.33 km/h.

Please note that the solution is rounded to two decimal places.